问题 选择题

能正确解释下列反应原理的离子方程式

A. AlCl3溶液中通入过量的NH3:Al3++4NH3·H2O=AlO2-+4NH4+

B.淀粉碘化钾试纸上滴稀硝酸变蓝:2I- + 4H+ + NO3-= I2 + NO↑+ 2H2O

C.电解MgCl2饱和溶液:

D.用碳酸钠溶液浸泡锅炉水垢:CaSO4 + CO32- CaCO3↓ + SO42-

答案

答案:D

A不正确,Al3+3NH3·H2O=Al(OH)3+3NH4

B、不正确,6I- + 8H+ + 2NO3-=3I2 + 2NO↑+ 4H2O

C、不正确,Mg2+2Cl+2H2OMg (OH)2↓+Cl2↑+H2

D、正确,沉淀的转化。

阅读理解

Body language shows all kinds of feelings and is sometimes more important than spoken language.A smile is a usual facial expression----it shows that you are friendly to others. However, it does not always mean that you are happy. A smile can hide other feelings, like anger, fear, or worry.

In most countries, nodding the head up and down shows agreement, while shaking the head means that you do not agree, or that you would not like to do something. If you stand holding your arms across your chest, you may be protecting yourself---just from a conversation you do not want! If you sit looking at the person you are talking to and then turn toward to him, it shows that you are interested. If you roll your eyes and turn your head away, most likely you do not believe what you are hearing, or you do not like what you hear.

小题1:Body language shows__________.

A.all kinds of feelings

B.some special feelings

C.nothing

D.only happy feelings小题2:When a person smiles, ______________.

A.it always shows he is very happy

B.it always means he hides some feelings

C.there may be some other feelings behind the smile.

D.it shows he is angry, worried or frightened.小题3:______________, nodding heads up and down shows he agrees with you.

A.In most countries

B.In all countries

C.In some countries

D.In Western Countries小题4:If a man stands holding his arms across his chest, it means __________.

A.he wants to protect himself from a conversation he doesn’t want

B.he is very interested in the conversation

C.he is pleased with the man he is talking to

D.he wants to know more about the man he is talking to

单项选择题